A house-elf is a magical creature which is immensely devoted and loyal to the one designated as their master. They serve wizards and witches and are usually found under the employment of old wizarding families taking residence in elaborate establishments, like mansions, and must do everything that their masters command unless they are freed. A house-elf can only be freed when their master presents them with clothes.

Magic

All house-elves have their own brand of powerful magic, which allows them to perform tasks, such as Apparating, where wizards and witches cannot.[2] More than just a mere housekeeper, a house-elf is a ruthless protector of their master, and will attack threats and enemies with great fury and strength and without even a moment's hesitation. In 1993, Dobby protected Harry Potter by using his magic to throw his former master, Lucius Malfoy, across the floor. However this is limited by their lack of wands, a fact that is shared with all non-human magical beings. However, unlike most magical beings, the house-elf is actually quite happy not to own a wand, as almost all house-elves never require one for the type of magic they perform (mostly domestic spells and Apparition). Apart from that, house-elves usually have to obtain permission from their masters before they could use their own brand of magic, as doing so without their consent would be treated as a sign of transgression, leading to the house-elf in question to apply self-inflicted injury upon himself or herself.

It is implied that with a wand and the proper knowledge, house-elves may be able to do other magic, as Winky was accused of using the Morsmordre spell to conjure the Dark Mark in the sky, though it was it was in fact cast by Bartemius Crouch Jr.Bartemius Crouch Sr. stated that Amos Diggory was implying that "I routinely teach my servants to conjure the Dark Mark," suggesting that it would have been possible for Winky to use the spell if she had the knowledge.[3]

Obedience

A house-elf must obey any commands given to them by their masters. At times, they seem to desire to disobey these orders, but as their master's orders are "the house-elf's highest law", they cannot. However, a house-elf may find loopholes within their master's or mistress's orders. For example, despite his loathing for Sirius Black, Kreacher could not disobey his direct orders. However, when Sirius yelled at him to "get out", which he meant to get out of the kitchen, Kreacher was able to interpret the command in a way that enabled him to leave number 12 Grimmauld Place and go to Sirius' cousins, Narcissa Malfoy and Bellatrix Lestrange. Also, during the 1996–1997 school year, Harry Potter ordered Kreacher to follow Draco Malfoy in order to find out what he was doing and where he was going, and carefully phrased his command to prevent Kreacher from contacting or alerting Draco. Kreacher, still reluctant to be owned by Harry, was unable to find a loophole in the orders about contacting Draco, but instead merely told Harry only about Draco's mundane daily activities.

Loyalty

Albus Dumbledore: "Give him an order. If he has passed into your ownership, he will have to obey. If not, then we shall have to think of some other means of keeping him from his rightful mistress."

The house-elf is so intensely loyal to their master that they will not allow themselves to be set free unless the master presents them with clothes. To symbolise this, they usually wear makeshift clothes made with found objects such as pillowcases and rags.[4] These clothes can become quite filthy, and yet the house-elf will not clean their clothes to further express they have no needs which are not specifically commanded to them by the master. House-elves will torture and maim themselves if they think it will please the master (or to punish themselves.)

House-elves not only serve one specific master, but the whole family of the master and whoever the house-elf is ordered by the master to serve. When Sirius Black was killed in 1996, Harry Potter inherited the House of Black's servant Kreacher.[2] At first they didn't even get along, because Kreacher considered his masters to be the House of Black. However, in due time Kreacher formed a fierce loyalty to Harry after Harry began to treat Kreacher with respect.[5]

House-elves are bound by magic to obey their masters' every command, but if the masters are cruel to the house-elves, then the elves would only obey their orders just enough to avoid breaking these magical binds. For example, when Harry Potter sent Kreacher on a mission to spy on Draco Malfoy, Kreacher did spy on him, but did not take note of any suspicious activity like Dobby did, instead noting only Draco's mundane activities such as eating and sleeping. However, one year later, Harry started being nicer to Kreacher at Hermione Granger's pleading, leading to much smoother compliance with Harry's orders.

Despite the seemingly horrid lifestyle that house-elves endure, house-elves seem to actually enjoy being enslaved. With few exceptions (Dobby being one of them), house-elves will feel insulted if their master attempts to pay them, give them pensions, or reward their service with anything except kindness. In 1995, when Hermione Granger began hiding clothes in Gryffindor Tower in an attempt to free the house-elves of Hogwarts, the house-elves felt rather insulted, and everyone except Dobby refused to clean the Gryffindor common room in protest.

Despite Hogwarts having had a large number of house-elves for centuries, it was only in their fourth year that Harry, Ron, and Hermione (rather shockingly) discovered their existence at Hogwarts, which happened inadvertently when the ghost of Sir Nicholas casually mentioned them being scared by Peeves the Poltergeist's tantrums. Sir Nicholas explained to them that the house-elves work in hiding, and it is considered the mark of a good house-elf that he or she does all the work but his/her existence is not even noticed.

It should be noted, however, that there are elements of coercion in some house-elves' loyalty. Kreacher disliked Sirius Black even when he was his master, and helped to sabotage Sirius by assisting Bellatrix Lestrange and Narcissa Malfoy, though this may have been easier for him since both witches had been born Blacks. Albus Dumbledore described Kreacher as "forced to do Sirius's bidding, because Sirius was the last of the family to which he was enslaved, but he felt no true loyalty to him".[6] Kreacher also initially despised serving Harry, only coming to be willingly loyal to him after Harry showed him kindness and respect and pointed out that by cooperating with him and his friends, Kreacher would be honouring the dying actions of Regulus Black, the late master he was very fond of. Hermione Granger pointed out that Kreacher was accustomed to "bad, even brutal treatment" and that he was "loyal to people who are kind to him".[5]

The house-elves of the House of Black were, in old age, beheaded and their heads were sickeningly stuffed and mounted on the house walls. This was, no doubt, considered by the house-elves as the very highest honour.

Winky was absolutely loyal to the Crouch family, and when she was dismissed for failure to keep Crouch Jr. under control, she suffered a mental breakdown, thinking that her release was the ultimate disgrace to her family.

While some house-elves were treated abysmally by their masters, some were genuinely loved and cared for. Some wizards treated their house-elves like adored pets or dolls, lavishing praise on them for doing their duties.

Mistreatment

"Kreacher is what he has been made by wizards, Harry. Yes, he is to be pitied. His existence has been as miserable as your friend Dobby's. He was forced to do Sirius's bidding, because Sirius was the last of the family to which he was enslaved, but he felt no true loyalty to him. And whatever Kreacher's faults, it must be admitted that Sirius did nothing to make Kreacher's lot easier."

In the past, house-elves have been treated very brutally by their owners. House-elves have no rights of their own and are looked on by wizarding societies as mere servants; they are often made patsies for the crimes of wizards. Even the government did not seem to care much for house-elves in the late 20th century; guidelines on house-elf welfare existed at least in 1996, but the Ministry did not enforce said guidelines.

For instance, Kreacher had to sleep in a cupboard near a kettle, where he made himself a den and was given no attention while Sirius Black was his master.

The house-elf Hokey was framed for the murder of Hepzibah Smith. She had not the self-worth or pride to defend herself from the charge and simply acknowledged the possibility of mistakenly giving her mistress poison.[2]

The house-elf Dobby was so mistreated and under appreciated by the Malfoy family that he independently sought out the aid and protection of Harry Potter in 1992.[4] Dobby insisted his higher duty was to protect Harry, even though Lucius Malfoy was the individual who perpetuated the danger at that time. When Dobby was freed, he ever after considered the service of Harry as his mission in life. In 1998, Dobby was slain by Bellatrix Lestrange in the act of protecting Harry's life.[5]
Voldemort forced Kreacher to drink the potion in which his Horcrux was hidden, simply to test the defence's effectiveness, and left him in the lake of Inferi. Also, Horace Slughorn made a house-elf test of his bottles of mead for poison (although he likely had antidotes on hand).

When a house-elf is mistreated, they will typically work just enough to obey their master's commands. However, if even the slightest loophole can be found in a master's orders, house-elves that are unhappy with their master will exploit that loophole to their advantage. The best way for a master to ensure full loyalty and compliance with their orders is to simply treat them properly. This was evidenced in 1997, when Hermione Granger convinced Harry Potter to be nicer to Kreacher. Soon, Kreacher began to accept his new master, and started serving him much more enthusiastically.

Hogwarts elves

"Yeah, it's a complicated issue. I would say that Hufflepuff gave- Hufflepuff did what was the most moral thing to do at that time, and we are talking about over a thousand years ago. So that would be to give them good conditions of work."

A veritable legion of house-elves are enlisted by Hogwarts School of Witchcraft and Wizardry. They work the kitchens, preparing feasts for the entire school. They also move trunks and baggage to and from rooms, clean dormitories, and presumably other areas of the castle as well. In 1994, they became angry with Hermione Granger as she made attempts to free them. Dobby and Winky, who came under Hogwarts' employ at the time, were considered disgraces to the rest of their colleagues due to Dobby being paid and receiving a vacation while Winky getting drunk out of self-pity. During the Battle of Hogwarts, the house-elves fought against the Death Eaters with Kreacher leading them. They defended their masters by using kitchen knives to stab at the attackers' ankles.[5]

S.P.E.W.

"You know, house-elves get a very raw deal! It’s slavery, that’s what it is! That Mr. Crouch made her go up to the top of the stadium, and she was terrified, and he's got her bewitched so she can't even run when they start trampling tents! Why doesn't anyone do something about it?"

In 1994, Hermione Granger, in outrage for the inhumane treatment of house-elves, created the student organisation S.P.E.W. - Society for the Promotion of Elfish Welfare - in an attempt to win rights for house-elves. She managed to get several students to join, paying a fee of two Sickles, though they only did so to stop her from badgering them. These students included Neville Longbottom, Ron Weasley, and Harry Potter. Some people refused to join S.P.E.W., like Fred and George Weasley, because they believed that the elves liked being treated the way they did. Hermione even tried to trick house-elves into picking up little hats and socks she had knitted and left around the Gryffindor dormitory so as to grant them freedom. The house-elves did not appreciate this gesture; on the contrary, they took it as an insult and refused to clean the common room, with the exception of Dobby.[7]

Physical appearance

House-elves are between two to three feet tall, with spindly arms and legs and over-sized heads and eyes. They have pointed, bat-like ears and high, squeaky voices. Rather than conventional clothing, house-elves wear discarded items like pillowcases and tea-towels. Though when they are freed, and when they are able to pay for proper clothing, they seem to not know how to wear it. For example, Dobby wore a single different styled sock on each foot, and in fact was under the impression that it wasn't correct to wear two matching socks.

Kreacher — Kreacher was an aged house-elf who served the House of Black with fanatical loyalty for most of his life, until he was left to Harry Potter upon the death of Sirius Black in 1996. He was particularly fond of "his mistress" Walburga Black, who died in 1985, but whose portrait still shrieked orders from the wall in the front hall of the Black house. After Mrs. Black's death, Kreacher let the home fall into disarray, doing little, if any, cleaning. He was also fiercely loyal to Regulus Black, for whom he fought in the Battle of Hogwarts along with many other house-elves.

The house-elves who formerly worked for the House of Black - These elves worked on the House of Black before Kreacher, and were beheaded once they were too old to carry a tea tray.

Kreacher's mother — The mother of Kreacher served as the house-elf of the Black family sometime before her son. When she became too old to carry a tea tray, she was beheaded, and her head was mounted on a plaque and hung on the wall above the front hall stairs at 12 Grimmauld Place. It was once Kreacher's sincere wish to suffer the same fate as his mother.

The house-elves who work in Hogwarts — At least a hundred strong, they live at Hogwarts and work in the kitchens. They wear uniforms made of tea towels.

Behind the scenes

House-elves are clearly based on the fairytale of 'The Elves and the Shoemaker' where a set of elves make shoes for a shoemaker until one day the shoemaker's wife makes them little clothes which he watches them receive. However, afterward they are never seen again.

According to the WOMBAT test, it is possible that house-elves have an average life expectancy of 200 years, cannot be ordered to kill themselves, breed infrequently and only with their master's permission, can override wizard enchantments, and have an allegiance to their home rather than its inhabitants.